When local authorities and legal firms carry out or advise on age assessments in the UK, one of the most important benchmarks remains the “Merton-compliant” framework. With changing legislation and increasing scrutiny—especially following the Nationality and Borders Act 2022 and the introduction of the National Age Assessment Board (NAAB)—it's more important than ever in 2025 to ensure assessments are conducted lawfully, ethically, and with due care.
But what exactly does Merton-compliant mean in today’s context—and how can local authorities ensure their assessments meet this standard?
What Is a Merton-Compliant Age Assessment?
The term comes from the case of R (B) v London Borough of Merton [2003], which set out key safeguards for local authorities assessing the age of an unaccompanied asylum seeker whose claimed age is in doubt.
A Merton-compliant assessment should:
Be fair and objective
Be carried out by two trained and experienced social workers
Allow the young person to be heard, with an appropriate adult present
Be based on a holistic view of the young person, rather than just appearance or behaviour
Provide clear, well-documented reasons for the decision
These principles remain the legal and professional standard across the UK.
What Does Merton-Compliance Look Like in 2025?
Age assessment practice has continued to evolve, with recent legislation allowing for the use of scientific methods such as x-rays and MRI scans. However, these approaches remain highly debated and, in our view, should not replace a comprehensive, welfare-led assessment that considers the young person’s full story, background, and needs.
Here are some key considerations in 2025:
Strong Evidence Gathering
Constructing a timeline of the young person’s life is one of the most important parts of an assessment. This includes details about education, family background, key life events, and the migration journey. A well-constructed narrative is often more reliable than focusing on how someone looks or behaves.
Cultural Awareness
Understanding the young person’s background is vital. Assessors should take time to research the norms of the individual's country of origin—especially around education, family roles, and significant milestones. This helps to avoid misinterpretation or applying assumptions based on UK norms.
Transparency and Record-Keeping
Every step of the assessment should be clearly recorded. Notes should explain how information was considered and why conclusions were drawn. This is essential in the event of a legal challenge.
Support for the Young Person
The young person should feel supported during the process. This includes having an appropriate adult present, access to an interpreter if needed, and being given the chance to understand what the assessment involves. Where relevant, legal advice should also be available—particularly if there is a plan to challenge the outcome.
Avoiding Bias and External Influence
Assessments must be impartial. Decisions should not be influenced by assumptions based on nationality, political narratives, or pressure from external agencies. This has become especially important with the introduction of the NAAB. Although its assessors are expected to follow Merton principles, organisations such as BASW have raised concerns about the independence of assessments carried out within the Home Office framework.
When Should Local Authorities Seek External Support?
In some cases, local authorities may decide to outsource assessments. This could be due to high caseloads, lack of capacity, or the need for an independent view. Other reasons might include complex legal challenges or safeguarding concerns that require external oversight.
Working with independent professionals helps ensure that assessments are thorough, fair, and fully in line with current legal standards.
Need Help with Merton-Compliant Age Assessments?
At Independent Migrant Services, we offer age assessments for local authorities and legal teams across the UK. Our approach is legally sound, culturally informed, and focused on the welfare of the young person.
If you would like to discuss how we can support your team, please get in touch.
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